The Experts below are selected from a list of 24465 Experts worldwide ranked by ideXlab platform
Qiang Yang - One of the best experts on this subject based on the ideXlab platform.
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failure and stability analysis of jinping i arch dam based on geomechanical model test and nonlinear numerical analysis
Rock Mechanics and Rock Engineering, 2019Co-Authors: Zhuofu Tao, Yaoru Liu, Li Cheng, Qiang YangAbstract:Jinping-I high arch dam is the highest arch dam (305 m) in the world, but the topography of its left and right sides of the arch is not symmetrical, which has a great impact on the overall stability of the arch dam. Based on the geomechanical model test and nonlinear numerical simulation, the evolution processes of cracks and failure during overloading in dam body and faults are demonstrated. Three safety factors of Jinping-I are gained and compared with other high arch dams. The safety factor of crack (K1) is 2.5, the factor of initial nonlinear deformation (K2) is 4.5 and the factor of the ultimate bearing capacity (K3) of Jinping-I is 7.5, indicating that the project has a high inherent safety. Treatments of foundation and weak zones are proved to be effective and then suggestions for Reinforcement are given. Additionally, the relationships between model test and numerical simulation based on the deformation Reinforcement Theory are studied, which verifies that the unbalanced force is an effective indicator for cracking.
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3d finite element modeling of directional hydraulic fracturing based on deformation Reinforcement Theory
Computers and Geotechnics, 2018Co-Authors: J Q Deng, Yaoru Liu, Qiang Yang, Yi Liu, Guoxin ZhangAbstract:Abstract The effective stress principle of Biot’s consolidation Theory is first introduced into deformation Reinforcement Theory to model directional hydraulic fracturing. The unbalanced force considering the effective stress of fluid is derived and a more effective vector type criterion of hydraulic fracture initiation and propagation is proposed. The unbalanced force magnitude indicates the fracture degree and direction clearly indicates the fracture propagation direction. The new Theory and method is first implemented into 3D finite element and the numerical modeling is verified by true tri-axial experiments. The investigation results indicate that unbalanced force can track and locate the hydraulic fracture propagation well.
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effective stress law for rock masses and its application in impoundment analysis based on deformation Reinforcement Theory
Journal of Central South University, 2018Co-Authors: Li Cheng, Yaoru Liu, Yuanwei Pan, Qiang YangAbstract:Reservoir impoundment is related to several hydraulic engineering concerns, including irreversible valley contractions, landslides and reservoir-induced earthquakes. However, these phenomena, such as valley contractions, are hardly to be explained by the conventional method. The scientific understanding of water effects during impoundment and their hazards to hydraulic structure are needed. The effective stress law for fissured rock masses is introduced in the elasto-plastic model employing the Drucker-Prager criterion and implemented in the three dimension (3D) nonlinear finite element method (FEM) program Three-dimensional FINite Element (TFINE). The slope deforms towards river-way during impoundment since the increasing pore pressure in fissures changes stress state and leads to additional plastic deformation in the rock materials. The value of Biot coefficient and the influence of water on rock materials are discussed in detail. Thus, the mechanism of slope deformation during the impoundment of Jinping-I arch dam is revealed, and the deformation is accurately measured. The application of the effective stress law provides a method to consider stress assessment, deformation evaluation and stability estimate of hydraulic structures during the impoundment process. This is a beneficial exploration and an improvement of hydraulic engineering design.
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stability analysis of earthquake induced rock slope based on back analysis of shear strength parameters of rock mass
Engineering Geology, 2017Co-Authors: Qingchao Lv, Qiang YangAbstract:Abstract High-steep rock slopes are much more likely to collapse and form weir body due to earthquake. Converting the weir body to hydraulic engineering is a good way to deal with natural disasters. However, it is difficult to evaluate the stability of earthquake-induced rock slope due to the lack of shear strength parameters of rock mass. Based on three-dimension nonlinear finite elements, deformation Reinforcement Theory was adopted, in which plastic complementary is used to measure the global stability of slope, and unbalanced forces is utilized to identify the damage region. The shear strength parameters has been determined through back analysis based on stability and failure status before and after earthquake and monitoring data after earthquake. Then the stability evaluation under static conditions, dynamic conditions and rainfall conditions has been carried out respectively. The results show that failure mode of the slope under seismic load is consistent with the actual situation when the lowest material parameters are used. The major failure mode of the slope is sliding along the fault F5, and local collapse of the hanging body at the top of the slope under dynamic or rainfall load. The local stability can be improved effectively by excavating and taking bolt anchorages on the top of the slope.
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long term stability analysis for high arch dam based on time dependent deformation Reinforcement Theory
International Journal of Geomechanics, 2016Co-Authors: Yaoru Liu, Qiang Yang, J Q Deng, Lijun XueAbstract:AbstractA high arch dam project causes an intense disturbance to its geological environment, with high in situ stress in the critical instability state, and the creep and damage of abutment rock mass resulting from the process of nonequilibrium evolution have a serious impact on the long-term safety of an arch dam. In this study, the long-term stability of an arch dam was evaluated with time-dependent deformation Reinforcement Theory (TDRT), in which plastic complementary energy (PCE) was used to judge the steady state or viscoplastic flow of the structure, the overstresses beyond the yield criterion were the driving force for nonequilibrium evolution of rock structures, and the unbalanced forces were the required Reinforcement forces. Based on a viscoplastic model and asymptotic stability analysis, the principle of minimum plastic complementary energy was proved for perfect and hardening yielding, in which viscoplastic structures deform to the limit steady state at which the PCE is minimized under time-i...
Andrew Koppelman - One of the best experts on this subject based on the ideXlab platform.
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how decentralization rationalizes oligarchy john mcginnis and the rehnquist court
Constitutional commentary, 2003Co-Authors: Andrew KoppelmanAbstract:"Decentralization" sounds wonderfully democratic. It implies that people are becoming masters of their own destinies, freed from the oppression of distant functionaries who neither know nor care about the particulars of their lives. Strangely, however, "decentralization" can sometimes be deployed to disguise oligarchic rule by an unaccountable elite. The paradox is starkly, if inadvertently, displayed in Professor John McGinnis's explication and defense of the Rehnquist Court's decisions on federalism and free association, "Reviving Tocqueville's America." Professor McGinnis argues that decentralization is a central theme of the Rehnquist Court's jurisprudence. He claims that this idea justifies the court's work, in the same way that John Hart Ely's representation-Reinforcement Theory justified much of the work of the Warren Court. His attempted justification fails, however, because the idea of decentralization cannot be implemented in the way he contemplates without policy determinations that are essentially legislative.
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how decentralization rationalizes oligarchy john mcginnis and the rehnquist court
Social Science Research Network, 2003Co-Authors: Andrew KoppelmanAbstract:“Decentralization” sounds wonderfully democratic. It implies that people are becoming masters of their own destinies, freed from the oppression of distant functionaries who neither know nor care about the particulars of their lives. Strangely, however, “decentralization” can sometimes be deployed to disguise oligarchic rule by an unaccountable elite. The paradox is starkly, if inadvertently, displayed in John McGinnis’s explication and defense of the Rehnquist Court’s decisions on federalism and free association, “Reviving Tocqueville’s America.” Professor McGinnis argues that decentralization is a central theme of the Rehnquist Court’s jurisprudence. He claims that this idea justifies the court’s work, in the same way that John Ely’s representation-Reinforcement Theory justified much of the work of the Warren Court. His attempted justification fails, however, because the idea of decentralization cannot be implemented in the way he contemplates without policy determinations that are essentially legislative. “Decentralization” thus becomes a rationalization for judicial oligarchy.
Yaoru Liu - One of the best experts on this subject based on the ideXlab platform.
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failure and stability analysis of jinping i arch dam based on geomechanical model test and nonlinear numerical analysis
Rock Mechanics and Rock Engineering, 2019Co-Authors: Zhuofu Tao, Yaoru Liu, Li Cheng, Qiang YangAbstract:Jinping-I high arch dam is the highest arch dam (305 m) in the world, but the topography of its left and right sides of the arch is not symmetrical, which has a great impact on the overall stability of the arch dam. Based on the geomechanical model test and nonlinear numerical simulation, the evolution processes of cracks and failure during overloading in dam body and faults are demonstrated. Three safety factors of Jinping-I are gained and compared with other high arch dams. The safety factor of crack (K1) is 2.5, the factor of initial nonlinear deformation (K2) is 4.5 and the factor of the ultimate bearing capacity (K3) of Jinping-I is 7.5, indicating that the project has a high inherent safety. Treatments of foundation and weak zones are proved to be effective and then suggestions for Reinforcement are given. Additionally, the relationships between model test and numerical simulation based on the deformation Reinforcement Theory are studied, which verifies that the unbalanced force is an effective indicator for cracking.
-
3d finite element modeling of directional hydraulic fracturing based on deformation Reinforcement Theory
Computers and Geotechnics, 2018Co-Authors: J Q Deng, Yaoru Liu, Qiang Yang, Yi Liu, Guoxin ZhangAbstract:Abstract The effective stress principle of Biot’s consolidation Theory is first introduced into deformation Reinforcement Theory to model directional hydraulic fracturing. The unbalanced force considering the effective stress of fluid is derived and a more effective vector type criterion of hydraulic fracture initiation and propagation is proposed. The unbalanced force magnitude indicates the fracture degree and direction clearly indicates the fracture propagation direction. The new Theory and method is first implemented into 3D finite element and the numerical modeling is verified by true tri-axial experiments. The investigation results indicate that unbalanced force can track and locate the hydraulic fracture propagation well.
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effective stress law for rock masses and its application in impoundment analysis based on deformation Reinforcement Theory
Journal of Central South University, 2018Co-Authors: Li Cheng, Yaoru Liu, Yuanwei Pan, Qiang YangAbstract:Reservoir impoundment is related to several hydraulic engineering concerns, including irreversible valley contractions, landslides and reservoir-induced earthquakes. However, these phenomena, such as valley contractions, are hardly to be explained by the conventional method. The scientific understanding of water effects during impoundment and their hazards to hydraulic structure are needed. The effective stress law for fissured rock masses is introduced in the elasto-plastic model employing the Drucker-Prager criterion and implemented in the three dimension (3D) nonlinear finite element method (FEM) program Three-dimensional FINite Element (TFINE). The slope deforms towards river-way during impoundment since the increasing pore pressure in fissures changes stress state and leads to additional plastic deformation in the rock materials. The value of Biot coefficient and the influence of water on rock materials are discussed in detail. Thus, the mechanism of slope deformation during the impoundment of Jinping-I arch dam is revealed, and the deformation is accurately measured. The application of the effective stress law provides a method to consider stress assessment, deformation evaluation and stability estimate of hydraulic structures during the impoundment process. This is a beneficial exploration and an improvement of hydraulic engineering design.
-
long term stability analysis for high arch dam based on time dependent deformation Reinforcement Theory
International Journal of Geomechanics, 2016Co-Authors: Yaoru Liu, Qiang Yang, J Q Deng, Lijun XueAbstract:AbstractA high arch dam project causes an intense disturbance to its geological environment, with high in situ stress in the critical instability state, and the creep and damage of abutment rock mass resulting from the process of nonequilibrium evolution have a serious impact on the long-term safety of an arch dam. In this study, the long-term stability of an arch dam was evaluated with time-dependent deformation Reinforcement Theory (TDRT), in which plastic complementary energy (PCE) was used to judge the steady state or viscoplastic flow of the structure, the overstresses beyond the yield criterion were the driving force for nonequilibrium evolution of rock structures, and the unbalanced forces were the required Reinforcement forces. Based on a viscoplastic model and asymptotic stability analysis, the principle of minimum plastic complementary energy was proved for perfect and hardening yielding, in which viscoplastic structures deform to the limit steady state at which the PCE is minimized under time-i...
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stability and Reinforcement analysis of rock slope based on elasto plastic finite element method
Journal of Central South University, 2015Co-Authors: Yaoru Liu, Q Chang, Qiang YangAbstract:The rigid body limit equilibrium method (RBLEM) and finite element method (FEM) are two widely used approaches for rock slope’s stability analysis currently. RBLEM introduced plethoric assumptions; while traditional FEM relied on artificial factors when determining factor of safety (FOS) and sliding surfaces. Based on the definition of structure instability that an elasto-plastic structure is not stable if it is unable to satisfy simultaneously equilibrium condition, kinematical admissibility and constitutive equations under given external loads, deformation Reinforcement Theory (DRT) is developed. With this Theory, plastic complementary energy (PCE) can be used to evaluate the overall stability of rock slope, and the unbalanced force beyond the yield surface could be the identification of local failure. Compared with traditional slope stability analysis approaches, the PCE norm curve to strength reduced factor is introduced and the unbalanced force is applied to the determination of key sliding surfaces and required Reinforcement. Typical and important issues in rock slope stability are tested in TFINE(a three-dimensional nonlinear finite element program), which is further applied to several representatives of high rock slope’s stability evaluation and Reinforcement engineering practice in southwest of China.
J Q Deng - One of the best experts on this subject based on the ideXlab platform.
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3d finite element modeling of directional hydraulic fracturing based on deformation Reinforcement Theory
Computers and Geotechnics, 2018Co-Authors: J Q Deng, Yaoru Liu, Qiang Yang, Yi Liu, Guoxin ZhangAbstract:Abstract The effective stress principle of Biot’s consolidation Theory is first introduced into deformation Reinforcement Theory to model directional hydraulic fracturing. The unbalanced force considering the effective stress of fluid is derived and a more effective vector type criterion of hydraulic fracture initiation and propagation is proposed. The unbalanced force magnitude indicates the fracture degree and direction clearly indicates the fracture propagation direction. The new Theory and method is first implemented into 3D finite element and the numerical modeling is verified by true tri-axial experiments. The investigation results indicate that unbalanced force can track and locate the hydraulic fracture propagation well.
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long term stability analysis for high arch dam based on time dependent deformation Reinforcement Theory
International Journal of Geomechanics, 2016Co-Authors: Yaoru Liu, Qiang Yang, J Q Deng, Lijun XueAbstract:AbstractA high arch dam project causes an intense disturbance to its geological environment, with high in situ stress in the critical instability state, and the creep and damage of abutment rock mass resulting from the process of nonequilibrium evolution have a serious impact on the long-term safety of an arch dam. In this study, the long-term stability of an arch dam was evaluated with time-dependent deformation Reinforcement Theory (TDRT), in which plastic complementary energy (PCE) was used to judge the steady state or viscoplastic flow of the structure, the overstresses beyond the yield criterion were the driving force for nonequilibrium evolution of rock structures, and the unbalanced forces were the required Reinforcement forces. Based on a viscoplastic model and asymptotic stability analysis, the principle of minimum plastic complementary energy was proved for perfect and hardening yielding, in which viscoplastic structures deform to the limit steady state at which the PCE is minimized under time-i...
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stability evaluation and failure analysis of rock salt gas storage caverns based on deformation Reinforcement Theory
Computers and Geotechnics, 2015Co-Authors: J Q DengAbstract:Abstract To perform a stability evaluation of underground gas storage caverns, the strength reduction finite element method is introduced into deformation Reinforcement Theory (DRT). The stability criterion of gas storage in caverns is established based on the K ∼ ΔE curve, where K is the strength reduction factor (SRF) and ΔE is plastic complementary energy (PCE). With respect to the state of instability, PCE quantitatively indicates the global stability of gas storage caverns, whereas the unbalanced force (UF) clearly specifies the local failure position and failure mode of gas storage caverns. A comparison between the results of geo-mechanical model testing and numerical simulation verifies the correlation between the UF and failure. DRT is applied to the stability evaluation and failure analysis of a gas storage double cavern, as well as the projected performance of rock salt gas storage caverns.
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time dependent behaviour and stability evaluation of gas storage caverns in salt rock based on deformation Reinforcement Theory
Tunnelling and Underground Space Technology, 2014Co-Authors: J Q Deng, Qiang YangAbstract:Abstract To simulate the time-dependent deformation and quantitatively evaluate the global stability of gas storage caverns in salt rock, the nonlinear viscoelastic, viscoplastic and viscodamage models are incorporated into the deformation Reinforcement Theory (DRT). A quantitative criterion for the long-term stability evaluation of gas storage caverns is established during the non-equilibrium evolution process based on a T –Δ E curve, where T is time and Δ E is plastic complementary energy (PCE). PCE quantitatively indicates the global stability of gas storage caverns. Over force clearly exhibits the local failure position and mode of gas storage caverns, determines the internal effective driving force of unrecoverable time-dependent deformation or damage evolution, and is also the required optimal Reinforcement force. DRT is applied to analyse the time-dependent deformation, global stability and local failure of a double-cavern of gas storage in salt rock.
Zhuofu Tao - One of the best experts on this subject based on the ideXlab platform.
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failure and stability analysis of jinping i arch dam based on geomechanical model test and nonlinear numerical analysis
Rock Mechanics and Rock Engineering, 2019Co-Authors: Zhuofu Tao, Yaoru Liu, Li Cheng, Qiang YangAbstract:Jinping-I high arch dam is the highest arch dam (305 m) in the world, but the topography of its left and right sides of the arch is not symmetrical, which has a great impact on the overall stability of the arch dam. Based on the geomechanical model test and nonlinear numerical simulation, the evolution processes of cracks and failure during overloading in dam body and faults are demonstrated. Three safety factors of Jinping-I are gained and compared with other high arch dams. The safety factor of crack (K1) is 2.5, the factor of initial nonlinear deformation (K2) is 4.5 and the factor of the ultimate bearing capacity (K3) of Jinping-I is 7.5, indicating that the project has a high inherent safety. Treatments of foundation and weak zones are proved to be effective and then suggestions for Reinforcement are given. Additionally, the relationships between model test and numerical simulation based on the deformation Reinforcement Theory are studied, which verifies that the unbalanced force is an effective indicator for cracking.
